Air and fuel control



Aug. 29, 1933. A. L. STEVENS AIR AND FUEL CONTROL Filed Sept. 29, 1928 3 Sheets-Sheet 2 nnullll "N (If; 2976,55, 6m. 2Z4

Aug. 29, 1933.

A. L. STEVENS AIR AND FUEL CONTROL Filed Sept. 29 1928 5 Sheets-Sheet 5 6 7721672 for:

Patented Aug. 29, 1933 UNITED STATES PATENT OFFICE Arthur L. Stevens, Evanston, Ill., assignor, by

mesne assignments, to Arthur L. Stevens Corporation, Chicago, IlL,

Ware

a Corporation of Dela- Application September 29, 1928 Serial No. 309,179.

19 Claims. (01. 158-119) This invention relates to fuel and air controls which, while being of general use and adaption, is particularly designed for use in conjunction with open hearth furnaces, and has for its ohject the proportional regulation of fuel and air from a single point of control whereby conditions are maintained for complete combustio in the furnace.

With the above and other objects in view, as will be apparent, this invention consists in the construction, combination and arrangements of parts all as hereinafter more fully described, claimed and illustrated in the accompanying drawings, wherein:

Fig. 1 is a side elevation of the present invention illustrating the same shown in conjunction with the air and oil valves;

Fig. 2 is a plan view of the control;

Fig. 3 is a vertical section taken along line 3-3 of Fig. 2 illustrating the unitary controlling mechanism for the regulation of the operation of the respective valves;

Fig. 4 is a horizontal section taken along section 4-4 of Fig. 1 to illustrate the construction of the fuel valve;

Fig. 5 is a vertical section taken along line 5--5 of Fig. 4 illustrating the details of the fuel valve construction;

Fig. 6 is a view taken at right angles to the plane of Fig. 5 and is a section taken along line 66 of Fig. 4 illustrating the fuel valve.

elements in elevation and the fuel valve casing in section; and

Fig. 7 is a horizontal section taken along line 7--'I of Fig. 1 illustrating the connections between the unitary control and the air valve.

In order to insure the economical operation of an open hearth furnace and to maintain proper metallurgical conditions within the furnace, it is essential that the proper proportions of fuel and air be admitted to the furnace chamber to create a neutral atmosphere therein. The present invention is designed to automatically regulate the proportions offuel and air delivered to the furnace chamber from a single control where- .by a neutral atmosphere will be created therein or any other predetermined relation of fuel to air may be created in the furnace. It is also among the objects of this invention to maintain the predetermined proportions of fuel and air delivered to the furnace chamber irrespective of the rate of firing or the quantity of fuel consumed.

As it happens that various grades of fuel frequently require different quantities of air for complete combustion, the present invention also contemplates an initial adjustment of the fuel valve so that it may be adapted to each different grade of fuel which the apparatus may be called upon to handle. Furthermore the present invention is designed to provide an adjustment of the fuel valve to compensate for any change or variation in the viscosity of the oil used as a fuel.

Reference being had more particularly to the drawings 10 designates a tubular stand or pedestal terminating at its lower end in a horizontal supporting plate 11. This plate 11 is designed to be secured in any suitable manner to the floor of the platform provided for the furnace operator. Below the supporting plate 11 is a hanger 12 having an extension 12' at its lower end. At the lower end of the hanger 12 and, in fact, at the junction between the hanger 12 and its extension 12' is located a bearing 13. A second hanger 14 is disposed below the supporting plate 11 and co-acts with the opposite side of the bearing 13 whereby the bearing 13 is rigidly and securely positioned between the lower ends of the hangers 12 and 14. The upper ends of the hangers 12 and 14 may be secured to the supporting plate 11 of the pedestal 10 or to the floor by means of" bolts 15 or other suitable securing means.

At its upper end the pedestal 10 is provided with a horizontal flange 16 to which is rigidly secured by means of the bolts 16', the base 1'? of the shell 18, the side thereof opposed to the base 1'7 being open. The base 17 of the shell 18 is centrally apertured and providedwith a bearing 19 at said aperture, for the mounting of the operating shafts to be hereinafter more fully described.

Projecting from one side of the shell 18 is a horizontal bearing 20 for the mounting of the control shaft 21 to theouter end of which is keyed a hand wheel 22 and which has a beveled spur gear 23 keyed to its inner end within the shell 18. A sleeve 24 is located within the shell 18 above the bearing 19 and rests thereon. At its upper end the sleeve 24 is offset outwardly to create a shoulder 25 and provide an upstanding flange 26 at the periphery of said shoulder 25. This flange 26 carries a segment 27 formed. integrally therewith uponthe side thereof adjoining the spur gear 23 with which it cooperates through the medium of a series of beveled teeth on the under surface of its end, meshing with the teeth of the beveled gear 23. It is thus apparent that as the hand wheel 22 is oscillated a similar movement will be imparted to the shaft 21 and the spur gear 23 thereby rotating the sleeve 24 by means of the segment 27.

A hollow tubular shaft 29 is mounted in the pedestal or stand 10 and operates in the bearing 19 in the base 17 of the shell 18. At its upper end the shaft 29 is keyed as at 30 to the sleeve 24, while at its lower end it terminates in or adjoins the bearing 13 located between the lower ends of the hangers 12 and 14. Manifestly the movement of the hand wheel 22 imparts an oscillatory movement within the limits of the segment 27 to the sleeve 24 which movement is, in turn, imparted to the tubular shaft 29 terminating and adjoining the bearing13.

A yoke 31 is secured to the lower end of the shaft 29 above the bearing 13 and includes the arms 32 which extend laterally therefrom and project between the hangers 12 and 14, said arms 32 being alined one with the other transversely of the shaft 29. The outer ends of these arms are pivotally connected to the air valve operating links 33, which extend to and co-operate with the shaft 35 of the air valve 34, theexterior shell 34 and shaft 35 only of which are disclosed in the present drawings. This valve may be of any suitable construction but preferably may correspond to the valve structure shown in Patent 1,356,568. The upper end of the shaft 35 of the valve 34 is provided with a yoke 37 including arms, similar to the arms 32 of the yoke 31, pivotally connected to the ends of the air valve operating links 33. The mechanism heretofore described accomplishes the adjustment and regulation of the air valve 34 from the hand Wheel 22 by the oscillation of the shaft 29 which, through the medium of the yokes 31 and 36 together with the links 33, oscillates the shaft 35 of the air valve concordantly therewith.

For the operation of the fuel valve a shaft 38 is mounted within thetubular shaft 29 and at is lower end projects below the bearing 13. At its upper end the shaft 38 is provided with a squared head 39 which is slideably received in a collar 40 having a square aperture for that purpose. The collar 40 is also provided with an outstanding flange 41, seated on the shoulder 25 of the sleeve 24 to which it is secured by the bolts 42. Thus, by this means the oscillation of the sleeve 24, as hereinbefore described, the fuel valve shaft 38 is oscillated. As will hereinafter be more fully described, it is desirable to adjust the fuel valve to deliver the proper amount of fuel for a predetermined quantity of air and this is accomplished by the longitudinal adjustment of the shaft 38 within the tubular shaft 29. For this purpose the upper end of the shaft 38 is prov ded with an interiorly threaded socket 43 in which is' mounted a threaded stud 44. A plate 45 is mounted in the open side of the shell 18 and constitutes a closure therefor, said plate being secured to the flange 26 of the sleeve 24 by means of the screws 46. This plate 45 is provided with a central aperture through which an extension 47 tubular shaft 29 by reason of the threaded engagement between the shaft 38 and stud 44. At its outer end the extension 4'3 is provided with a lock nut 50 which clamps against the block 49. This lock nut 50 is protected by a cover 51 which is hinged to the block 49 as at 52 and at its opposite sideis provided with an ear 52' for co-operation with a lug 53 formed from the block.

A locking element 54, which may be the bow of a padlock, pierces both the lug 53 and ear 52' to secure them in locked position covering the lock nut 50. When it is desired to adjust the shaft 38 longitudinally in the tubular shaft 29 the ear 52' of the cover 51 may be released from the lug 53, after which, the cover 51 may be raised above its pivots 52. The lock nut 50 may then be loosened after which the block 49 may be turned in the desired direction to accomplish the proper adjustment of the shaft 38. This movement of the block either raises or lowers the shaft 38 through the threaded engagement of the stud 44 with the socket 43 of the shaft and the slidable connection between the shaft and the collar 40. When the proper adjustment has been attained the lock nut 50 may be tightened and the cover 51 lowered and locked in place. The adjustment just described of the shaft 38 is for the purpose of adapting the fuel valve, to be described, to various grades, types and character of fuel and this adjustment is only made once for each type or grade of fuel used.

In order to determine the adjustment of the shaft 38 for each particular grade or type of fuel 4 the block 49 is provided with an indicator 55 coacting with the graduations 56 placed on the plate 45 concentrically with respect to the stud 44 and adjoining the center of said plate. Thus, when it is determined that a certain type or grade of fuel requires such an adjustment of the shaft 38 that the indicator 55 is located at 90, it is only necessary to adjust the shaft 38 so that the indicator will be at 90 whenever this particular grade or type of fuel is used. In this manner every distinctive grade or type of fuel used will have its particular designation in the scale of graduations 56 so that when that particular grade or type of fuel is used it will only be necessary to I adjust the indicator 55 to the particular graduation 56 corresponding to that fuel and maintain it at that point so long as such fuel is being used. The determination of that graduation corresponding to a particular grade or type of fuel will be hereinafter more fully described.

The fuel valve which cooperates with the shaft 38-is carried at the lower end of the extension hanger 12' of the main hanger 12 and is secured thereto by a plate 57 which is bolted to a transverse plate 58 at the lower end of the hanger. This plate 57 carries the upper half 59 of the valve casing, the lower half 60 thereof being secured to the upper half 59 by the bolts 61 piercing the flanges projecting laterally from the abutting edges of the respective halves 59 and 60 of the casing. The lower half 60 of the valve casing is provided with a drain cook 62 while the upper half is provided with a bearing 63 for the lower end of the shaft 38. This bearing 63 is surrounded by flange 64 which cooperates with a packing plate 65 having a boss 66 which enters into the space between the flange 64 and the shaft 38. Adjustment screws 67 are provided and the space below the boss 66 between the flange 64 and the shaft 38 is filled with a suitable packing 68. Thus a non-leaking joint is provided between the shaft 38 and the valve casing, the packing 68 of which may be compressed or loosened by means of the screws 6'7. The upper section 59 of the valve casing is also provided with an outlet pipe 69 leading to the point of combustion while the lower half 60 of the valve casing is provided with a fuel inlet '70.

Within the valve casing is a bearing 71. This bearing '71 is cylindrical in formation and extends from the upper half 59 to the lower half 60 of the valve casing. Medially of its ends it is provided with an outstanding flange 72 which is received and clamped between the halves of the valve casing whereby the bearing 71 is rigidly and fixedly located within the casing. A sleeve'or cylindrical valve '73 is slidably and rotatably mounted within the bearing '71 and is closed at its upper end '74 where it is secured to the lower end of the shaft 38. Thus it is apparent that as the shaft 38 is oscillated or rotated or as it is moved longitudinally the cylindrical or sleeve valve '73 is similarly moved. To insure a non-leaking joint between the valve sleeve '73 and the bearing '71 the latter is provided with a groove in the lower end of the face thereof bearing against the sleeve valve '73 in which is mounted suitable packing '75. The compression of this packing '75 is controlled by a flange '76 which enters the groove and operates upon the packing '75 and is carried by a plate '77 adjustably secured to the flange 72 of the caring '71 by means of the bolts '78.

From the foregoing it will be seen that the fuel enters the lower half 60 of the valve casing through the pipe '70 located below the flange '72 of the bearing '71. The flange '72 of the bearing constitutes a partition between the halves 59 and 60 of the valve casing so that the only access the fuel delivered to the lower half of the casing has to the upper half 59 thereof, which it must reach to enter the fuel outlet 69 leading to the point of combustion, is through the bearing '71 and cylindrical sleeve valve '73. This is accomplished by providing a port '79 in the wall of the bearing '71 and a similar port in the sleeve valve '73. These ports '79 and 80 are so relatively positioned that they co-act or register to permit the passage of fuel from the lower half 60 of the valve casing to the upper half 59 thereof, from which it is free to pass out through the pipe 69.

The rotation of the shaft 38 moves the sleeve valve '73 relatively to the bearing '71 decreasing or increasing the size of the aperture created by the registration of the ports '79 and 80 dependent upon the direction of the rotation of the shaft 38 by increasing or decreasing the degree of registration of said ports. By varying this degree of registration on the part of the ports '79 and 80 the quantity of fuel passing from the lower half of the valve casing 60 to the upper half 59 and thence to the outlet pipe 69, is determined.

The mechanism heretofore described, with reference to the movement of the hand wheel 22 causing a rotation of the shafts 29 and 39, increases or decreases the quantity of fuel entering the outlet pipe 69 by oscillating the sleeve valve '73 within the bearing '71 and simultaneously increasing or decreasing the quantity of air delivered to the point of combustion. The increase or decrease of the air in proportion to the increase or decrease of the fuel consumption is simultaneous and is regulated and controlled entirely by the hand wheel 22. A series of graduations 81 are provided on the plate 45 which coact with the indicator 82 carried by the bearing 20 and act as an indicator for determining the rate of firing the furnace.

Frequently the quality, grade or character of the fuel varies so that a given quantity of one vfuel or grade of fuel will require more or less air than a different fuel or grade of fuel in order to obtain complete combustion. For the purpose of adjusting the present invention to accommodate all types and grades of fuel, the longitudinal adjustment heretofore described, with reference to the shaft 38, is provided. The raising or lowering of the shaft 38 raises or lowers the sleeve valve '73 and determines the vertical available width of the registering ports '79 and 80. If, for instance, the sleeve valve '73 is raised from the position shown in Fig. 5, the vertical dimension or width of the available space through which the fuel may pass through the ports '79 and 80 is reduced. When the sleeve valve '73 reaches its upper limit of movement the ports '79 and 80 are completely out of registration while the positioning of the sleeve valve '73 at its lower limit of movement places the ports '79 and 80 in full registration. By thusvarying the size of the available space through which fuel may pass through the ports '79 and 80, the quantity of fuel passing into the upper half 59 of the valve casing for a given quantity of air delivered to the point of combustion, is varied. In this manner the quantity of air delivered at a given adjustment of the apparatus is not changed, but on the contrary where a fuel requires more air for complete combustion less fuel is delivered and when the fuel used requires less air for complete combustion more fuel is delivered.

To determine the adjustment of the shaft 38, a flue gas analysis may be made to determine whether or not the quantity of any fuel or grade of fuel entering the furnace is using all of the air admitted to the furnace and the shaft may be adjusted as heretofore described to increase the quantity of fuel delivered and thereby consume all of the air admitted to the furnace,.if there is an excess of air, or to decrease the quantity of fuel if the air admitted is not sufficient to cause complete combustion. When the combustion is complete the position of the indicator 55 may be fixed and noted and when that particular grade of fuel is again used the shaft 38 may be adjusted so that the indicator occupies the position noted. Once the shaft 38 has been adjusted longitudinally for a certain grade of fuel, .no further change or adjustment is necessary as long as that particular grade of fuel is being used, irrespective of the rate of firing or the manipulation of the controls.

From the foregoing it is to be noted that by the adjustment of the hand wheel 22 the rate of firing may be increased or decreased and that the ratio of fuel to air necessary for complete -fixed to the air valve shaft, aconnection between said gear and said fuel valve shaft, and. means for rotating said gear.

3. The combination with an air valve, of, a fuel valve, a shaft for operating said air valve, a shaft for operating said fuel valve, and means for operating said shafts in unison, comprising a sleeve fixed to the air valve shaft, a gear carried by said sleeve, a connection between said sleeve and said fuel valve shaft, and means for operating said gear.

4. The combination with a pair of valves, a tubular shaft for operating one of said valves, a shaft within said tubular shaft for operating the other of said valves, connections between said shafts and their respective valves, a sleeve fixed to one of said shafts, a collar fixed to said sleeve and having a connection with the other of said shafts, and means for operating said sleeve.

5. The combination with a pair of independent valves, a tubular shaft for the operation of one of said valves, a shaft for the operation of the other of said valves mounted in said tubular shaft, connections between said shafts and their respective valves, a sleeve secured to one of said shafts, a collar secured to said sleeve and having a sliding connection with the other of said shafts, means for operating said sleeve, and means cooperating with the shaft slidably connected with said collar for adjusting said shaft relative to said collar.

6. The combination with a pair of independent valves, a tubular shaft for operating one of said valves, a second shaft mounted within said tubular shaft for operating the other of said valves, a sleeve secured to said tubular shaft, means for rotating said sleeve, a collar secured to said sleeve and having a slidable connection with said second shaft, and means for adjusting said second shaft, comprising a fixed stud having threaded co-operation with the end of said second shaft.

7. In a regulating device for proportioning the quantities of air and fuel for combustion, a source of air at constant pressure, a source of fuel at constant pressure, an air valve having an orifice the size of whichmay be regulated from closed to full open position, a fuel valve having an orifice, the size of which may be regulated from closed to full open position, synchronized means for operating both of said valves so that the ratio of their effective areas remains constant in all positions, and independent means for adjustingthe ratio of the effective areas of said valves.

8. In a regulating device for proportioning the relative quantities of fueland air forcombustion,

the combination with an air valve, of a. fuel valve connected to and opening in synchronism with said air valve, and means coacting with said fuel .valve for altering the effective area of its port, independently of the opening and closing movement thereof.

9. In a regulating device for proportioning the relative quantities of fuel and air for combustion, comprising a pedestal having a tubular shaft mounted therein, a second shaft mounted within said tubular shaft, an operating member mounted on said pedestal and having a connection with said tubular shaft, means whereby said second shaft is slidably connected to said tubular shaft for movement in unison therewith, a. fuel valveconnected to said second shaft and an air valve connected to said tubular shaft.

10. In a regulating device for proportioning the relative quantities of fuel and air for combustion,

comprising a pedestal having a tubular shaft mounted therein, a second shaft mounted within said tubular shaft, an operating member mounted on said pedestal and having a connection with said tubular shaft, means whereby said second shaft may rotate inunison with said tubular shaft under the influence of said operating member and be slideably adjustable longitudinally of said tubular shaft, a fuel valve connected to said second shaft having its effective area adjusted by the longitudinal adjustment of said second shaft within the tubular shaft, and an air valve connected with the tubular shaft.

11. In a regulating device for proportioning the relative quantities of fuel and air for combustion, comprising a pedestal having a tubular shaft mounted therein, a second shaft mounted within said tubular shaft, an operating member mounted on said pedestal and having a connection with said tubular shaft, a slideable connection between said tubular shaft and said second shaft whereby the latter may be adjusted longitudinally within the former and rotate in unison therewith, means for adjusting said second shaft longitudinally as aforesaid, a fuel valve connected to said second shaft having its efiective area adjusted by the longitudinal adjustmentof the second shaft, and an air valve connected to said tubular shaft.

12. In a regulating device for proportioning the relative quantities of fuel and air for combustion, comprising a pedestal having a tubular shaft mounted therein, a second shaft mounted within said tubular shaft, an operating member mounted on said pedestal and having a connection with said tubular shaft, a slideable connection between saidtubular shaft and said second shaft whereby the latter may be adjusted longitudinally within the former and rotate in unison therewith, means for adjusting said second shaft longitudinally as aforesaid, means for fixing said second shaft in its adjusted positions, a fuel valve connected to said second shaft having its effective area adjusted by the longitudinal adjustment of the second shaft, and an air valve connected to said tubular shaft.

13. In a combustion control device, a, fuel valve having a definite area, an air valve having a definite area, common control means for operating said valves simultaneously so that the effective rea of one is directly proportioned to the effective area of the other for all operations of said control means and means for independently changing the area of one of said valves to vary said proportion.

14. In a combustion control device, a first valve having a definite area, a second valve having a definite area, means for operating said valves simultaneously, said means being operative to vary the eifective area of one valve with respect to the other in direct proportion as the setting of the first valve is varied and means for changing the ratio of said proportions.

15. In a combustion control device, a first valve having a definite area, a second valve having a definite area, control means for operating said valves simultaneously, said means being operative to vary the effective area of one valve withrespect to the other in direct proportion as the setting of one of the valves is varied from open to closed position, and means for changing a definite area, control means for operating said valves simultaneously, said means being operative to vary the effective area of one valve with respect to the other in direct proportion as the setting of one 01' the valves is varied from open to closed position and means independent 01' said control means for changing the ratio of said proportion.

1'Z. In a combustion control device,'a first valve having a definite area, a second valve having a definite area, common control means for poerating said valves simultaneously, said means being operative to vary the effective area 01 the second valve with respect to the first valve in direct proportion as the setting of the first valve varies from open to closed position and means for changing the ratio of said proportion.

18. In a combustion control device, a first valve having a definite area, a second valve having a definite area, control means for operating said valves simultaneously, said means being operative to vary the eflective area of one valve with respect to the other in direct proportion as the setting of one of the valves is varied from open to closed position, means for changing the ratio of said proportion, and means for indicating the effective opening of each valve.

- respect to the other in direct proportion as the setting of one of the valvestis varied from open to closed position, means for changing the ratio of said proportion, and means for indicating the ratio of said proportion.

ARTHUR L. STEVENS. 

